Scroll-type volume displacement apparatus with an orbiting thrust bearing

ABSTRACT

A scroll-type volume displacement apparatus with an orbiting thrust bearing. A scroll element of the first end plate in a fixed scroll engages with a scroll element of the second end plate in an orbiting scroll, the fixed scroll and the orbiting scroll are set in the main housing respectively. The purpose of the apparatus is to set the thrust ball bearing between the orbiting scroll and the base shell, which can orbit along the orbiting scroll, so as to balance the potential shake generated in the orbiting movement along the orbiting scroll through the multi-group thrust ball bearings. And, by the sealed contact between the orbiting scroll and the thrust ball bearing, the axial deviating force of the orbiting scroll can seal the pressure chamber to keep the slight contact of the front and behind face of the two scrolls which engages with each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and the benefit of Chinese Patent Application No. CN201110150716.6, filed on Jun. 7, 2011, the entire content of which is incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The invention related to a scroll-type volume displacement apparatus, especially to a scroll-type volume displacement apparatus with an orbiting thrust bearing.

2. Description of the Related Art

In the field of machinery, scroll-type fluid displacement apparatus are used in compressor and expander, scroll is a cylinder element with a spiral cross-section extended on the end plate. Generally one is a fixed, which called fixed scroll. Another scroll with a spiral cross-section conjugates with the spiral cross-section of fixed scroll, and the scroll makes circle movement relatively to the fixed scroll, which also called orbiting, that is orbiting scroll.

The cylinders of these two conjugated spiral scrolls engage each other to form a line contact.

At least one sealed gas pressure chamber forms between a couple of line contact and the end plate. When an orbiting scroll makes orbit motion to the fixed scroll, the line contact on the spiral sidewall will move along the sidewall, thus to change the size of the sealed gas chamber. The direction of the orbit motion will decide whether the seal gas chamber will expand or compress the fluid.

U.S. Pat. No. 7,467,933, FIG. 1 is an example of a longitudinal sectional view of a scroll expander with single scroll structure, see FIG. 1, a longitudinal sectional view of a scroll expander with single scroll structure, scroll apparatus 10 comprises a main housing 20, a base shell 70, a rotation drive shaft 40, a fixed scroll 50 and an orbiting scroll 60, orbiting scroll 60 has a second end plate 61; base shell 70 connects with main housing 20, fixed scroll 50 and orbiting scroll 60 mount in main housing 20, the front of base shell 70 has thrust bearing 71, thrust bearing 71 contact in a way of slide friction with the sealed boss 64 on the backend of the second end plate 61 of the orbiting scroll 60, and forms a pressure chamber 83 between the sealed boss 64 and front plane of the thrust bearing 71, compressed gas enter the pressure chamber 83, which makes the pressure chamber 83 generates axial bias force, and thrusts the orbiting scroll 60 along the axial to the fixed scroll 50.

The way to achieve sealed contact between elements is to set one or more sealed elements like sealed boss and seal. But there are two problems. First, when the seal element orbits to the orbiting scroll, because when the orbiting scroll orbits under the action of several force and moment will shake along the axial of the spindle S1-S1, seeing N-N in FIG. 1, it will make the contact of sealed boss 64 and thrust bearing 71 become loose. Second, under the status of no oil, sealed elements and thrust bearing will generate friction power loss and the sealed element will attrit when they make slide contact.

SUMMARY OF THE INVENTION

The invention provides a scroll-type volume displacement apparatus with the structure which can improve the reliability of the axial compliance structure of scroll and improve the energy efficiency of scroll apparatus, it has thrust bearing which can orbit in a similar way to orbiting scroll, which makes no relative motion between orbiting scroll and thrust bearing, the back of the orbiting scroll and the orbiting thrust bearing generate sealed contact through sealed elements (for example sealed boss, O-type ring, lip seal etc), and which forms sealed pressure gas chamber. The gas pressure generated between orbiting thrust bearing and orbiting scroll and flexible force of sealed element will make axial compliant motion, and axial bias force to orbiting scroll generated by other forces will also make axial compliant motion, the axial compliant motion is that orbiting scroll makes motion to fixed scroll. Therefore the life of sealed element and the reliability and the friction power loss can be improved in this way.

A scroll-type volume displacement apparatus with an orbiting thrust bearing, comprises a main housing, a base shell, a fixed scroll and an orbiting scroll, wherein also comprises an orbiting trust bearing, said orbiting thrust bearing is connected with a bearing block end plate of said orbiting scroll by pins, said orbiting thrust bearing orbits in a similar way to the orbiting scroll.

Further, said orbiting thrust bearing sliding fits with said pins, said orbiting scroll drives said orbiting thrust bearing orbit by said pins.

Further, said orbiting scroll contains a second end plate, a pressure chamber forms between said orbiting thrust bearing and said second end plate of said orbiting scroll, the pressure of said pressure chamber roles in said second end plate, and makes said orbiting scroll orbit relatively to said fixed scroll.

Further, there is fixed thrust bearing between said second end plate of said orbiting scroll and said base shell, said fixed thrust bearing connects to said orbiting thrust bearing, which makes said fixed thrust bearing bear the axial thrust who bore by said orbiting thrust bearing.

Further, said fixed thrust bearing comprises fixed thrust ball bearing and orbiting thrust ball bearing, said fixed thrust ball bearing mounts on said base shell, said orbiting thrust ball bearing roles in said fixed thrust ball bearing, at the same time, said orbiting thrust ball bearing orbits in a similar way relatively to said fixed thrust ball bearing.

Further, said fixed thrust ball bearing and said orbiting thrust ball bearing bear the axial thrust of said orbiting thrust ball bearing.

The invention provides a scroll-type volume displacement apparatus which can improve axial and radial scroll compliance structure, it has thrust bearing between orbiting scroll and base shell which can orbit in a similar way to orbiting scroll, which forms sealed pressure gas chamber through the sealed element contact between orbiting scroll and orbiting thrust bearing, generated axial bias force.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of a scroll expander with single scroll structure;

FIG. 2 is a schematic vertical of the invention a scroll-type volume displacement apparatus with an orbiting thrust bearing;

FIG. 3 is a transverse cross-sectional view along line 3-3 in FIG. 2. FIG. 3 shows the structure of orbiting thrust bearing driven by orbiting scroll;

FIG. 4 is a longitudinal sectional view along line 4-4 in FIG. 3. The different between FIG. 2 is the section rotates 90° along the main axis S1-S1;

FIG. 5 is a longitudinal sectional view of the invention of a scroll-type volume displacement apparatus with an orbiting thrust bearing;

FIG. 6 is a sectional view of two-way thrust bearing structure in the invention of a scroll-type volume displacement apparatus with an orbiting thrust bearing;

FIG. 6A is a schematic diagram of up thrust bearing of the two-way thrust bearing structure;

FIG. 6B is a schematic diagram of fixed thrust bearing of the two-way thrust bearing structure;

FIG. 6C is a schematic diagram of down thrust bearing of the two-way thrust bearing structure.

DESCRIPTION OF SOME EMBODIMENTS

The following gives the first embodiment of a scroll-type volume displacement apparatus with an orbiting thrust bearing.

FIG. 2 is a schematic vertical of the invention a scroll-type volume displacement apparatus with an orbiting thrust bearing, seeing FIG. 2, a scroll-type volume displacement apparatus with an orbiting thrust bearing 10, comprises a main housing 20, a base shell 70, a fixed scroll 50 and an orbiting scroll 60. The fixed scroll 50 has a first end plate 51, a scroll element 52 fixes on the first end plate 51, the scroll element 52 fixes on it and extends outside; orbiting scroll 60 has a second end plate 61, the second end plate 61 fixes on the scroll element 62, the scroll element 62 fixes on it and extends outside; the first end plate 51 with the scroll element 52 and the second end plate 61 with the scroll element 62 close to each other, so the scroll element 52 engages with the scroll element 62, and the scroll element 52 below the second end plate 51, the scroll element 62 bellows the first end plate 51, the scroll element 52 and the scroll element 62 keep 180° phase angle displacement and radial displacement equals orbiting radius Rot When orbiting scroll 60 orbits to the fixed scroll 50, at least one sealed gas chamber between the scroll element 52 and the scroll element 62, which change the volume of the gas chamber through the slide of the engagement surface between the first end plate 51 and the second end plate 61.

When the orbiting scroll makes circular movement to the fixed scroll, i.e. the orbiting movement, it can form line contact between the motion of first end plate sidewall and second end plate sidewall.

The fixed scroll 50 and the orbiting scroll 60 are set in the main housing 20, and support the fixed scroll 50 through the main housing 20, the end plate 51 of the fixed scroll 50 and the main housing 20 are set as a whole structure, the base shell 70 connects to the main housing 20, the base shell 70 faces to the end of the orbiting scroll 60.

A rotation drive shaft 40 comprises a central axis 41, a crankshaft 42, the crankshaft 42 is set in an end of the central axis 41, the central axis 41 runs through the middle part of the base shell 70, and the crankshaft 42 near the end of the orbiting scroll 60, the crankshaft 42 can drive orbit bearing 63 through joint 64, orbit bearing 63 is the back of the orbiting scroll 60, thus which drives the orbiting scroll 60 make circular movement to the fixed scroll 50, that is orbiting; the front and rear portions of the central axis 41 are supported by bearing 33 and bearing 34 respectively, the bearing 33 and the bearing 34 are set to the base shell 70 respectively, and supported by the base shell 70, which makes the central axis 41 set in the base shell 70 rotatable, meanwhile, which plays a role in locating the central axis 41 through bearing 33 and bearing 34. There is a motor 35 between bearing 33 and bearing 34, the motor 35 located in the base shell 70, and supported by the base shell 70, the central axis runs through the motor 35, which makes the central axis 41 can rotate to the axis S1-S1 driven under the motor 35.

There is an inlet 80 on the main housing 20. There is a suction channel 81 between the main housing 20 and the fixed scroll 50 and the orbiting scroll 60, when the working fluid such as air can enter the suction channel 81 through the inlet 80 on the main housing 20. There is a central gas chamber 82 in the middle of the orbiting scroll 60 and the fixed scroll 50, There is a pressure chamber 83 between the rear face of the orbiting scroll 60 and the orbiting thrust bearing 172, the pressure gas introduced from the pressure chamber which is appropriately located between the fixed scroll 50 and the orbiting scroll 60 to communicate with the pressure chamber 83 through an appropriate channel 88; the working fluid which has entered the suction channel 81 is sucked between the fixed scroll 50 and the orbiting scroll 60 to become pressure chamber, and which is compressed during the motion of orbiting of the orbiting scroll 60, then which is transformed to the central gas chamber 82, finally discharged through the vent 84 located in the middle of the first end plate 51 of the fixed scroll 50.

FIG. 3 is a transverse cross-sectional view along line 3-3 in FIG. 2 shows the structure of orbiting thrust bearing driven by orbiting scroll, FIG. 2 and FIG. 3 show that the invention has a center drive crank shaft—slip joints and peripheral crank pins—swing structure (CSPS structure), it comprises central drive joint 64, crank pin bearing 260, peripheral parts 160 a, bearing bore 161 a, fixed crank 162 a, crank joint bearing 163 a, eccentric hole 166 a, peripheral parts 170 a, bearing bore 171 a, fixed crank 172 a, crank joint bearing 173 a, crank joint bearing 174 a, crank pin 175 a, eccentric hole 176 a, synchronizer 177, synchronizer bearing 177 a, synchronizer bearing 177 b, synchronizer bearing 177 c etc, which support ability for the orbiting scroll to orbit axial and radial, it follows the Chinese Patent awarded to the applicant, patent number is ZL200610121150.3 “improved scroll-type displacement compressor with full compliance float-scroll”, no repeat here.

FIG. 4 is a longitudinal sectional view along line 4-4 in FIG. 3. The different between FIG. 2 is the section rotates 90° along the main axis S1-S1, see FIG. 2, FIG. 3 and FIG. 4. The orbiting thrust bearing 172 connects with bearing end plate 93 of orbiting scroll 60 by pin 95 a and 95 b. The orbiting thrust bearing 172 sliding fits with the pins 95 a and 95 b. When the orbiting scroll 60 orbits, it drives the orbiting thrust bearing 172 to orbit through the pins 95 a and 95 b.

There is a fixed thrust bearing between the second end plate 61 of the orbiting scroll 60 and the base shell 70, the fixed thrust bearing is connected to the orbiting thrust bearing 172. Therefore, it makes the fixed thrust bearing bear the axial thrust which was bore by the orbiting thrust bearing 172. The fixed thrust bearing comprises fixed thrust ball bearing 104 and orbiting thrust ball bearing 102, the fixed thrust ball bearing 104 mounts on the base shell 70, the orbiting thrust ball bearing 102 plays role in the fixed thrust ball bearing 104, meanwhile, the orbiting thrust ball bearing 102 orbits in a similar way relatively to the fixed thrust ball bearing 104.

There is a sealed pressure chamber 83 formed by the sealed element 90 and the sealed element 92 (such as: O-type ring, lip seal etc) between the orbiting thrust ball bearing 172 and the end plate 61 of the orbiting scroll 60, the pressure of the pressure chamber 83 plays role in the second end plate 61 of the orbiting scroll 60, and that makes the orbiting scroll 60 orbit relatively to the fixed scroll 50. Because the orbiting thrust ball bearing 172 orbits in an extreme similar way like the orbiting scroll 60, so the sealed elements 90 and 92 have minimum relative motion between the orbiting scroll bearing end plate 93 and the orbiting thrust bearing 172, thus to reduce the abrasion of the sealed elements and friction power loss. Three couples of double-thrust ball bearing structure (FIG. 2 only draw one couple, the fixed thrust ball bearing 104 and the orbiting thrust ball bearing 102) support the axial thrust bore by the orbiting thrust bearing 172, and make the orbiting thrust bearing 172 orbit in a similar way relatively to the orbiting scroll 60. Besides, for the orbiting thrust bearing 172 is a bi-orbiting thrust bearing, it can bear the axial thrust from front and back of the axis.

The following gives the second embodiment of a scroll-type volume displacement apparatus with an orbiting thrust bearing.

FIG. 5 is a longitudinal sectional view of the invention of a scroll-type volume displacement apparatus with an orbiting thrust bearing. The structure of the fixed scroll 50 and the orbiting scroll 60 showed in the figure, the working principle of the structure is similar with the above detailed described first embodiment, no repeat here.

FIG. 6 is a sectional view of two-way thrust bearing structure in the invention of a scroll-type volume displacement apparatus with an orbiting thrust bearing, FIG. 6A is a schematic diagram of up thrust bearing of the two-way thrust bearing structure, FIG. 6B is a schematic diagram of fixed thrust bearing of the two-way thrust bearing structure, FIG. 6C is a schematic diagram of down thrust bearing of the two-way thrust bearing structure, see FIG. 5, FIG. 6, FIG. 6A, FIG. 6B and FIG. 6C. There is a fixed thrust bearing between the second end plate 61 of the orbiting scroll 60 and the base shell 70, the fixed thrust bearing comprises down thrust bearing 74, fixed bearing 73 and up thrust bearing 72. The drive bearing 65 and the orbiting drive bearing 261 drive the up thrust bearing 72 and the down thrust bearing 74 to orbit in a similar way like the orbiting scroll 60.

The up thrust bearing 72 is a disc shape, there is a hole 72 a in the middle of the up thrust bearing 72, three stepped holes 72 b and three threaded holes 72 c are average set around the up thrust bearing 71.

The fixed bearing 73 is a disc shape, there is a hole 73 a in the middle of the fixed bearing 73, a stepped hole 73 b is concentrically arranged on the periphery of the fixed bearing 73, three countersunk screw holes 73 c and three holes 73 d are average set around the fixed bearing 73; three countersunk head screws 77 run through the three countersunk screw holes 73 c relatively, and then fix the fixed bearing 73 on the base shell 70.

The down thrust bearing 74 is a disc shape, there is a hole 74 a in the middle of the down thrust bearing 74, three stepped holes 74 b and three threaded holes 74 c are average set around the down thrust bearing 74.

The up thrust bearing 72, the fixed bearing 73 and the down thrust bearing 74 are ranged in an order. Three spacer sleeves 75 separate the up thrust bearing 72 from the down thrust bearing 74, which to make the distance larger than the thickness of the fixed bearing 73; three countersunk head screws 76 fix the up thrust bearing 72 and the down thrust bearing 74 together, the up thrust bearing 72 and the down thrust bearing 74 are also fixed together with the orbiting drive bearing 261, and the inside diameter of the orbiting drive bearing 261 sliding fits with the drive bearing 65. The diameter difference between the diameter of the spacer sleeve 75 and the diameter of the hole 73 d of the fixed bearing 73 equals to two times of the orbiting radius of the orbiting scroll 60, that is orbiting diameter, meanwhile, the distance between the axis S1-S1 of the central axis 41 and the axis S2-S2 of the crank pin 44 also equals the orbiting diameter of the orbiting scroll 60. When the crank pin 44 drives the drive bearing 65, and further drives the orbiting drive bearing 261, finally that makes the up thrust bearing 72 and the down thrust bearing 74 orbit, at the same time, the orbiting drive bearing 261, the up thrust bearing 72 and the down thrust bearing 74 can make axial slide together. The spacer sleeves 75 which are installed in the hole 73 d prevent the up thrust bearing 72 and the down thrust bearing 74 from rotating efficiently.

Finally, the up thrust bearing 72 and the down thrust bearing 74 bear the axial thrust from the orbiting thrust bearing 172.

The second end plate 61 has sealed element 90 and sealed element 93, the sealed element 90 and the sealed element 93 can adopt seals like lip seal or O-type seal etc, there is also a pressure chamber 83 between the up thrust bearing 72 and the second end plate 61, it separates the pressure chamber 83 from the surrounding area through the sealed element 90 and the sealed element 93. When scroll apparatus starts, the elastic preload of the sealed element 90 and the sealed element 93 ensures that when the orbiting scroll 60 pushes to the fixed scroll 50, there is slight axial contact between the two engaged scrolls. When scroll apparatus starts, the pressure of the pressure chamber between the fixed scroll 50 and the orbiting scroll 60 can communicate with the pressure gas chamber 83 through the channel.

In the application of vacuum pump, the inlet is in the atmosphere when the vacuum pump starts, the exhaust side is also in the atmosphere. The gas pressure in the pressure gas chamber 83 is higher than the atmosphere pressure, which exerts a backward axial thrust to the orbiting scroll 60 (that is to the motor). The selection of the size of the sealed element 90 and the sealed element 93 determines the area of the pressure gas chamber 83, the force plays role in the back of the second end plate 61 of the orbiting scroll 60 from the compressed gas introduced by the pressure gas chamber of the scroll, and the elastic pretightening force exerted by the sealed element 90 and the sealed element 93, that the two forces exceed the axial separation force exerted by the compressed gas which is compressed in the front of the orbiting scroll 60, the axial force pushes the orbiting scroll 60 to the fixed scroll 50 along the axial to achieve the slight contact of the two engaged scrolls, thus to make the pressure gas chamber maintain good seal from the radial direction. The invention has a center drive crank shaft—slip joints and peripheral crank pins—swing structure (CSPS structure), it also makes the orbiting scroll element 62 maintain contact with the fixed scroll 52 from the radial direction, so to maintain the seal of the pressure gas chamber from the tangential direction. Meanwhile, under the effect of the gas pressure in the pressure gas chamber 83, the up thrust bearing 72 backwards to make sliding contact with the fixed bearing 73, that is the direction of the motor, the latter bears the axial thrust.

When the scroll vacuum pump continues to work, the pressure of the suction side gradually declines, the gas pressure in pressure gas chamber 83 is lower than the atmosphere, the force plays role in the back of the second end plate 61 of the orbiting scroll 60 from the pressure gas which is lower than the atmosphere introduced from the compressed gas chamber of the scroll, and elastic pretightening force exerted by the sealed element 90 and the sealed element 93, and the resultant of the atmospheric pressure plays role in all the outside surfaces of the non-sealed chamber of the orbiting scroll 60, the three forces push the orbiting scroll 60 to the fixed scroll 50 along the axial to achieve the slight contact of the two engaged scrolls. At this time, the atmospheric pressure which is played role in the back of the up thrust bearing 72 will push the up thrust bearing 72 and the down thrust bearing 74 forward(that is the direction of the fixed scroll), the up thrust bearing 72 and the down thrust bearing 74 move forward, and they are stopped by the fixed bearing 73, but the front of the up thrust bearing 72 and the back of the down thrust bearing 74 will make sliding contact, the latter bears the axial thrust, so to avoid the big axial thrust playing role in the scroll, because of the pressure difference between the atmosphere and vacuum.

The invention of a scroll-type volume displacement apparatus with an orbiting thrust bearing, the purpose is to set the thrust ball bearing between the orbiting scroll and the base shell, which can orbit along the orbiting scroll, so as to balance the potential shake generated in the orbiting movement along the orbiting scroll through the multi-group thrust ball bearings, and by the sealed contact between the orbiting scroll and the thrust ball bearing, the axial deviating force of the orbiting scroll can seal the pressure chamber, at the same time, the pressure gas chamber keeps the slight contact of the front and behind face of the two scrolls which engages with each other through the sealed elements in it. 

What claimed is:
 1. A scroll-type volume displacement apparatus with an orbiting thrust bearing, comprises a main housing (20), a base shell (70), a fixed scroll (50) and an orbiting scroll (60); wherein also comprises an orbiting trust bearing (172), said orbiting thrust bearing (172) is connected with a bearing block end plate (93) of said orbiting scroll by pins (95 a, 95 b), said orbiting thrust bearing (172) orbits in a similar way to the orbiting scroll (60).
 2. A scroll-type volume displacement apparatus with an orbiting thrust bearing as claimed in claim 1, wherein said orbiting thrust bearing (172) sliding fits with said pins (95 a, 95 b), said orbiting scroll (60) drives said orbiting thrust bearing (172) orbit by said pins (95 a, 95 b).
 3. A scroll-type volume displacement apparatus with an orbiting thrust bearing as claimed in claim 1, wherein said orbiting scroll (60) contains a second end plate (61), a pressure chamber (83) forms between said orbiting thrust bearing (172) and said second end plate (61) of said orbiting scroll (60), the pressure of said pressure chamber (83) roles in said second end plate (61), and makes said orbiting scroll (60) orbit relatively to said fixed scroll (50).
 4. A scroll-type volume displacement apparatus with an orbiting thrust bearing as claimed in claim 1, wherein there is fixed thrust bearing between said second end plate (61) of said orbiting scroll (60) and said base shell (70), said fixed thrust bearing connects to said orbiting thrust bearing (172), which makes said fixed thrust bearing bear the axial thrust who bore by said orbiting thrust bearing (172)
 5. A scroll-type volume displacement apparatus with an orbiting thrust bearing as claimed in claim 4, wherein said fixed thrust bearing comprises fixed thrust ball bearing (104) and orbiting thrust ball bearing (102), said fixed thrust ball bearing (104) mounts on said base shell (70), said orbiting thrust ball bearing (102) roles in said fixed thrust ball bearing (104), at the same time, said orbiting thrust ball bearing (102) orbits in a similar way relatively to said fixed thrust ball bearing (104).
 6. A scroll-type volume displacement apparatus with an orbiting thrust bearing as claimed in claim 5, wherein said fixed thrust ball bearing (104) and said orbiting thrust ball bearing (102) bear the axial thrust of said orbiting thrust ball bearing (172). 